Lock seam for pipe



Feb. 21,1939. D, A. MILLER ET AL 2,147,775

LOCK SEAM FOR PIPE Filed May 20, 1938 v i H fa-a H I v 5 {07F 4 4344 3?}; 34 3 M DONALD ,4. MILLER l7 0 Mweo/v N. MILLER INVENTORS ATTORNEYS Patented Feb. 21, 1939 U TED PAT ENT OFFICE 2447.775 men s'ia'AM FOR me Danna. A. Miller, New Philadelphia, and Myron M. 'Miller, Dover, Ohio Application my 20, 1938, Serial No. 209,022

This invention relates to lock seams for pipe, and more especially it relates. to "improved longitudinal seams of Stovepipe sections by which the opposite'lateral margins of sheet metal structures are joined to provide tubular lengthsof Stovepipe.

In the manufacture of stovepipe sections of the character mentioned; the lateral margins of the sheet metal structures are provided with interlooking formations, and the structures bent "sub.-

stantially to'circular shape, but with the locking margins spaced apart topermit nesting of a pin-- rality of the structures to-conserve space and shipping expense. Subsequently the margins of lo the sections are brought together and locked by interengagement of the locking formations on said margins, such locking beingeffecte'd by the tradesman or by the ultimatepurch'as'er.

The chief objects of theinvention are'to provide an improved stove'pipe of the character mentioned that will comprise a more securely locked seam'than heretofore has been available; to provide a stovepipe sectionof which the looking formationsare disposed interiorly of the-pipe, and

presentlittle or no gap on the eiiterior'of 'the pipe; to provide for ease of assembly without requiring the use of tools; and t'o'provide aseam of the character mentioned. that will not open even when the pipe is subjectedtogreat'heat.

More specifically the inventionaims to provide a stovepipe seam of which the locking formations are interengaged at two spaced points transversely of the pipe. Other objects will be manifest asthe specification proceeds.

Of the accompanying drawing:

Figure 1 is .a perspective view'of a Stovepipe section provided with an improved lock seam andconstituting one embodiment of the invention;

Figure 2 is a fragmentary sectional view of the locking formations shown in Fig. 3, showing the same in open or unlocked position; t

Figure 3 isasection on a larger' scale'on the line 3-3 of Fig. l;

Figure 4 is a fragmentary end viewof'alocking formation constituting another embodiment of the invention, the parts being shown in un locked position;

Figure 5 is an end view of 'theparts shown in Fig. Lin locked'positiori;

Figure 6 is a view similar to Fig. 4 showing another embodiment of the invention; and

Figure 7 is a View of the parts shown in Fig.6 in locked position.

Referring to the drawingpthereis shown at lflin Fig. 1 a typical stove pipe section of which one end portion thereof is crimped asshown at H to facilitate the joining of adjacent pipe sections. The crimping does not extend to the lateral edges of the pipe section, and therefore does 5 not interfere with the lockingformations thereon. The seam is formed by interlocking. formations on the opposite lateral margins of the pipe structure, one of said formations being a. female member designated llla andthe other formation 10 being a male member designated lllb. The details of the interlocking formations Illa, lilb are best shown in Figs. 2 and 3 to which attention is directed.

In the female member l-Ua of the lock seam 15 the marginal portion of the sheet metal of the pipe section is folded'inwardly at l2 and backwardly upon itself as shown at l3,'upon the interior of the pipe section, the metal then being folded in reverse direction as shown at 14, in 20 parallel spaced relationto the portion l3, toprovide a pocket or groove l5 therebetween. The metal constituting the inner wall of the pocket [5 extends substantially beyond themouth of the pocket that is, beyond the fold I2, and at 25 its terminal region is bent outwardly to provide a locking shoulder It, which preferably isinclinedsomewhat-toward said pocket. At spaced points longitudinally of the/pocket l5, the metal of-the inner wall thereof -is-angularly incised at 30 H, H to form respective tongues of metal [8, the latter being bent so ;as to extend into, the pocket 15 withtheir free ends directed toward, but spaced from, the bottom or-closed end of the pocket. Thetongues it constitute looking for- 35 mations for-engagement with a locking portion of the male member Nib as presently will be explained. r

I In the male member llIb'of-th'e lock seam the marginal portionyof the sheet metal isbentin- 4,0 wardly and backwardly upon itself at 20, and'in- Wardly and ,forwardlyupon itself at El, thus'providing a reverse fold of which the fold 2| con stitutes a locking-formation, the distance between fold 2i) and fold 21 being substantially the same 45 as the distance between. fold. l2 'and the raw edge of locking shoulder llirof the female member of the seam. From the reverse fold described, the sh'eet. metal-extends forwardly beyond' the bend 2B inthe formof atongue lz 50 that has its terminal portion reversely folded uponitself as shown at 23, throughout the entire length of the pipe section, the innermost bend of the fold, which is spaced somewhatfrom the edge of the member, being designated 24 55 and constituting a locking formation. The distance from the bend 20 to the extreme edge of fold 23 is slightly less than the depth of the pocket I5 of the female member Illa, and the distance from the locking formation 24 to the edge of fold 23 is slightly less than the distance from the free end of tongue |8 of the female member to the bottom of said pocket I5.

The male and female members of the lock seam are shown in their assembled or interlocked relation in Fig. 3. To connect the two margins of the pipe structure it is only necessary to force the male member |0b into the female member Illa. In this operation the reversely folded free edge of the tongue 22 of the male member, including the locking formation 24, passes between the locking shoulder I6 and bend |2 of the female member and enters the pocket I5 thereof. Moving toward the bottom of pocket I3, the fold at the leading edge of the male member passes over the tongues I8, the flexibility of the latter enabling this readily to be accomplished. The tongues I8 spring back to normal position as soon as the fold of the male member has passed, and are thus in position to engage the locking formation 24 of the male member to prevent retraction of the latter. When the leading end of the male member reaches the bottom of the pocket I5, locking formation 2| of the male member has passed beyond the raw edge of looking shoulder I6 of the female member and readily slips into place beside said shoulder, the bend 20 of the male member then being disposed closely adjacent the bend |2 of the female member so that the exterior of the pipe presents a smooth, practically unbroken surface.

After the male and female members of the lock seam are interengaged as described, they will not come apart under severest service conditions. The superiority of the seam is the result of the use of two interlocking regions at spaced points transversely of the seam, whereby the several advantages set out in the foregoing statement of objects are achieved. The locking of the seam is readily effected manually without the use of tools of any kind.

In the embodiment of the invention shown in Figs. 4 and 5, the male member |0b is identical with the male member previously described so that no further description thereof is required. In the female member, designated We, the marginal portion of the pipe section is folded inwardly at 25 and backwardly upon itself as shown at 26, upon the interior of the pipe section, the metal then being folded in reverse direction as shown at 21, in parallel spaced relation to the portion 26 to provide a pocket or groove 28 therebetween. The metal constituting the inner wall of the pocket 28 is reversely folded at 29, within the pocket, the innermost bend of said fold constituting a locking shoulder 30 disposed within the pocket and extending continuously the entire length thereof. The distance from the locking shoulder 30 to the closed side of the pocket 28 is slightly greater than the distance between the terminal-edge 20 and the looking formation 23 of the male member IOa. From the reverse fold 29 the metal of the inner wall of the pocket extends forwardly beyond the mouth of the pocket, and at its terminal region is bent outwardly to provide a locking shoulder 3| similar to the locking shoulder I6 of the previously described embodiment. V

When the male and female members I0b, Illc, respectively, are in interlocked relation, locking formation 24 is engaged by locking formation 30 within the pocket 28, and locking formation 2| is engaged by locking formation 3| exteriorly of the pocket 28, but interiorly of the pipe. Since the locking formations 24, 30 are of double thickness of the metal, an especially strong interlock is provided, and which readily cannot become disengaged. This embodiment of the invention possesses all the advantages inherent in the firstdescribed embodiment, and may be somewhat stronger for the reason that interlock of formations 24, 30 is continuous throughout the full length of the pipe.

The embodiment of the invention shown in Figs. 6 and 7 comprises a female member Ifle and a male member ID). In the female member the marginal portion of the pipe section is folded inwardly at 34 and backwardly upon itself as shown at 35, upon the interior of the pipe, the metal then being folded in reverse direction as shown at 36, in spaced relation to the portion 35, to provide a pocket or groove 31 therebetween. The metal constituting the inner wall of the pocket 3! extends well beyond the mouth of the pocket, that is, beyond the fold 34, and is of double thickness, the raw edge of the metal sheet being disposed within the pocket, in spaced relation to the closed side of the latter, said raw edge constituting a locking formation 38. Laterally beyond the mouth of the pocket 31, the outer or marginal portion of the double-thickness structure is bent outwardly with relation to the axis of the pipe section to provide a locking formation or shoulder 39, said shoulder preferably being inclined somewhat toward the fold 34. its double wall, the locking formation 39 is materially strengthened so that it will not straighten out under heat and/or lateral strain, and it is not readily bent or damaged in transit.

In the male member I0) of the scam the marginal portion of the pipe section is bent inwardly and backwardly upon itself at 4|, and inwardly and forwardly upon itself at 42, thus providing a reverse fold of which fold 42 constitutes a locking formation. From the reverse fold described the metal extends forwardly beyond the bend 4| to provide a tongue 43 the terminal marginal portion of which is folded inwardly upon itself at 44, the raw edge of the tongue constituting an underlying locking formation 45.

Interlocking of the male and female members of the seam is accomplished by inserting the tongue 43 into the pocket 31 of the female member lfle. When said tongue reaches the closed side of the pocket the locking formation 45 of 1 the tongue drops into edge-to-edge relation with the raw edge locking formation 38 in said pocket, thus preventing retraction of the tongue. When the locking formations 38, 45 are in interlocked relation, the fold 42 of the male member will slip into juxtaposition with the locking shoulder 39 of the female member, the arrangement being such as to provide the double interlock characteristics of the invention.

The primary advantage of the invention is that the seam will not open even under severest service conditions. Furthermore, the pipe presents a neat appearance due to the fact that the interlocking elements are disposed interiorly of the pipe, there being but a slight seam-gap exposed to view from the exterior of the pipe. In each embodiment of the invention, the metal of the inner wall of the pocket extends laterally a substantial distance beyond the mouth of the pocket, thus being adapted to serve as a guide to facili- Because of tate the insertion of the male element into the pocket.

Modification may be resorted to without departing from the spirit of the invention, or the scope thereof as defined by the appended claims.

What is claimed is:

l. A stovepipe section having an interlocking seam consisting of a male member along one edge thereof and a female member along the opposite edge, said male member comprising a reversely bent portion comprising a locking formation and a tongue, the terminal marginal portion of the latter being folded inwardly upon itself to provide a second locking formation spaced laterally of the first mentioned locking formation, said. female member comprising an inwardly reversely bent portion defining a pocket in which the tongue of the male member is re oeivable, a locking formation within said pocket interengageable with the locking formation on the terminal marginal portion of the tongue, the inner wall of said pocket extending beyond the mouth thereof and being formed with an angular portion constituting a locking formation that is interengageable with the first mentioned locking formation of the male member.

2. A Stovepipe section having an interlocking seam consisting of a male member along one edge thereof and a female member along the opposite edge, said female member comprising a reversely bent portion defining a pocket and having a look ing formation disposed entirely within the pocket and a locking formation disposed exteriorly thereof, said male member comprising a reversely bent portion defining a locking formation and a tongue, the latter having a second locking formation coextensive with its terminal margin, said tongue being insertable in the pocket of the female member to effect interengagement of the locking formations on the male and female members.

3. A stovepipe section having an interlocking seam consisting of a male member along one edge thereof and a female member along the opposite edge, said female member comprising an inturned reversely bent portion defining a pocket, the inner wall of said pocket having a longitudinally extending series of spaced apart locking formations formed therein entirely within the pocket, said inner pocket wall extending beyond the mouth of the pocket and being formed with a locking shoulder at its outermost extremity, said male member comprising a reversely bent portion defining a locking formation that is engageable with the last mentioned locking formation of the female member, and a tongue that is receivable in the pocket of said female member and is formed with a marginal locking formation that is coextensive with the length of the seam and interengageable with the locking formations in the said pocket.

i. A stovepipe section having an interlocking seam consisting of a male member along one margin thereof and a female member along the opposite margin, said female member comprising an inturned reversely bent portion defining a pocket, the inner wall of said pocket being incised at spaced points longitudinally thereof and integral tongues struck out therefrom, said tongues being disposed entirely within the pocket and having raw edges facing the closed side of the pocket, said inner Wall of the pocket extending beyond the mouth of the pocket and formed thereat with an outwardly extending locking shoulder, said male member comprising a reversely bent portion defining a locking formation that is interengageable with the last mentioned locking formation of the female member, and a tongue that is receivable in the pocket of said female member and is formed with an inturned marginal fold defining a locking formation that is interengageable with the raw edges of the locking tongues in said pocket.

5. A, stovepipe section having an interlocking seam consisting of a male member along one edge thereof and a female member along the opposite edge, said female member comprising an inturned reversely bent portion defining a pocket, one wall of said pocket being reversely folded upon itself to define a locking formation entirely within the pocket, the inner wall of the pocket extending laterally beyond the mouth thereof and formed thereat with an outwardly extending locking shoulder, said male member comprising a reversely folded portion defining a locking formation that is interengageable with the last mentioned locking formation on the female member, and a tongue that is receivable Within the pocket of said female membar and is formed with a marginal fold defining a locking formation that is interengageable With the locking formation in the said pocket.

6. A stovepipe section having an interlocking seam consisting of a male member along one edge thereof and a female member along the opposite edge, said female member comprising an inturned reversely bent portion defining a pocket, the inner wall of said pocket reversely folded upon itself to define a locking formationwithin the pocket and extending longitudinally thereof, said inner wall of the pocket extending laterally beyond the mouth of the pocket and formed at its extremity with an outwardly turned locking shoulder, said male member comprising a reversely folded portion defining a locking'formation that is engageable with the said locking shoulder of the female member, and a tongue that is insertable into the pocket of said female member, said tongue having its terminal portion folded under upon itself to define a locking formation that is interengageable with. the locking formation within said pocket.

7. A Stovepipe section having an interlocking seam consisting of a male member along one edge thereof and a female member along the other edge, said female member comprising an inturned reversely bent portion defining a pocket, the inner wall of said pocket extending beyond the mouth of the pocket in double wall thickness and being angularly bent at the terminal region of said double wall portion to provide a locking formation exteriorly of the pocket, the raw edge of the structure being disposed within the pocket and constituting a second locking formation, said male member comprising a reversely bent portion roviding a locking formation engageable with the first mentioned locking formation on the female member, and a laterally extending tongue insertable in the pocket of said female member, the terminal portion of said tongue including a locking formation engageable with the raw edge locking formation located within said pocket.

DONALD A. MJLLER. MYRON M. MILLER. 

